Heat storage tank

ABSTRACT

A heat storage tank  10  comprises a plastic container  11  for storing engine cooling water, an inflow pipe  30  and an outflow pipe  31  communicating with the interior of plastic container  11  and formed to project from plastic container  11 , and a heat-insulating layer  13  arranged to cover the whole periphery of plastic container  11  to insulate the heat of the engine cooling water in plastic container  11.    
     Heat-insulating layer  13  is arranged to cover the roots of pipes  30, 31.  Therefore, the heat radiation of the engine cooling water from the bases of pipes  30, 31  can be suppressed thereby preventing a reduction in heat insulation effect.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to a heat storage tank for storing and insulatinga liquid.

2. Description of the Related Art

A cooling system for promoting the warm-up of a water-cooled internalcombustion engine of an automotive vehicle has conventionally beenproposed in which a heat storage tank for storing and insulating theengine cooling water flowing out of the water-cooled engine is arrangedin the cooling water circuit and the high-temperature cooling waterstored in the heat storage tank is introduced to the engine toaccelerate engine warm-up. This makes it possible to utilize theextraneous heat of the engine effectively and reduce the fuelconsumption from the overall viewpoint of the vehicle operation.

Generally, the heat storage tank has a double heat-insulating structureincluding an inner cylindrical tank of stainless steel making up a heatstorage tank body and an outer cylindrical tank of stainless steel,wherein the space between the inner and outer cylindrical tanks is keptsubstantially in vacuum.

SUMMARY OF THE INVENTION

However, the heat storage tank described above requires two tanksincluding inner and outer cylindrical tanks which results in increasedcost.

In view of the above, the object of this invention is to provide a heatstorage tank for reducing cost while at the same time maintaining theinsulation effect.

In order to achieve the above object, according to this invention, thereis provided a heat storage tank comprising a tank body (11) for storinga fluid, pipes (30, 31) communicating with the interior of the tank bodyand formed to project from the tank body, and a heat-insulating layer(13) arranged to cover the whole periphery of the tank body includingthe roots of the pipes and thus to insulate the heat of the fluid in thetank body.

As a result, the use of only a single tank body can reduce the costwithout using two tanks, i.e. inner and outer cylindrical tanks.

In addition, since the heat-insulating layer is arranged in such amanner as to cover the whole periphery of the tank body including thebases of the first and second pipes, heat radiation from the bases ofthe first and second pipes can be suppressed, thereby making it possibleto maintain the heat insulation effect.

Incidentally, the reference numerals inserted in the parenthesesfollowing the names of the respective means described above representthe correspondence with the specific means, respectively, included inthe embodiments described below.

The present invention may be more fully understood from the descriptionof preferred embodiments of the invention, as set forth below, togetherwith the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagram showing a configuration of a cooling water circuitused for a heat storage tank for automotive vehicles according to thisinvention.

FIG. 2 shows the external appearance of the vehicle heat storage tankshown in FIG. 2.

FIG. 3 is a sectional view showing the vehicle heat storage tank shownin FIG. 2.

FIG. 4 is a perspective view showing the interior of the vehicle heatstorage tank shown in FIG. 2.

FIG. 5 is a diagram showing the flow of the engine cooling water in thevehicle heat storage tank shown in FIG. 2.

FIG. 6 is a diagram showing the assembly steps for the vehicle heatstorage tank shown in FIG. 2.

FIG. 7 is a diagram explaining the forming of the film layer shown inFIG. 6.

FIG. 8 is a diagram explaining the forming of the film layer shown inFIG. 6.

FIG. 9 is a diagram explaining the forming of the film layer shown inFIG. 6.

FIG. 10 is a diagram explaining the forming of the film layer shown inFIG. 6.

FIG. 11 is a diagram explaining the forming of the film layer shown inFIG. 6.

FIG. 12 is a diagram explaining the forming of the film layer shown inFIG. 6.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 1 shows a configuration of the cooling water circuit using thevehicle heat storage tank according to an embodiment of the invention.

The cooling water circuit includes a heat storage tank 10, a four-wayvalve 20, a heater core 30 and an electrically-operated pump 40. Heatstorage tank 10 is for insulating and storing the engine cooling water.Four-way valve 20 connects the outlet side of one of a cylinder head 50and a cylinder block 51 of the engine to the inlet side of at least oneof heater core 30 and heat storage tank 10.

Heater core 30, which makes up a vehicle air conditioning system, is aheat exchanger for heating the air with the engine cooling water.Electrically-operated pump 40 is a circulation pump for supplying theengine cooling water toward the inlet side of each of cylinder head 50and cylinder block 51.

In the cooling water circuit, a connection is established only betweenthe outlet side of cylinder block 51 and the inlet side of heat storagetank 10 by four-way valve 20 while the temperature of the cooling wateris low. As a result, the cooling water stored in heat storage tank 10can be supplied into cylinder block 51 thereby accelerating the warm-upof cylinder block 51.

In the process, the inlet side of heater core 30 is shut off by four-wayvalve 20, and therefore the cooling water from heat storage tank 10flows only to cylinder block 51. Thus, the warm-up of cylinder block 51can efficiently promoted.

Upon a subsequent temperature increase of the cooling water to a middlelevel, four-way valve 20 closes the communication between the outletside of cylinder block 51 and the inlet side of heat storage tank 10,while at the same time connecting the outlet side of cylinder head 50and the inlet side of heater core 30.

In the process, the engine cooling water (hot water) can be kept incylinder block 51, and therefore the engine warm-up is accelerated.Further, the engine cooling water heated by cylinder head 50 iscirculated between cylinder head 50 and heater core 30, and thereforethe air can be heated by heater core 30.

Upon subsequent increase of water temperature to a high level, four-wayvalve 20 connects the outlet side of cylinder head 50 to the inlet sideof heater core 30 and the inlet side of heat storage tank 10. Then, theengine cooling water flows into heat storage tank 10, and therefore theengine cooling water (hot water) for the next warm-up can be stored inheat storage tank 10.

The structure of heat storage tank 10 will be explained. FIG. 2 showsthe appearance of heat storage tank 10, and FIG. 3 is a sectional viewtaken in the plane A in FIG. 2.

Heat storage tank 10, as shown in FIG. 2, is cubic and has an inflowpipe 30 and an outflow pipe 31 projected outward from the lower part ofthe side wall thereof. Specifically, heat storage tank 10, as shown inFIG. 3, includes a plastic container (tank body) 11 and aheat-insulating member 15 surrounding the whole outer periphery ofcontainer 11. Heat-insulating member 15 contains both the exterior oftank body 11 formed as a polyhedron and the base portions of inflow pipe30 and outflow pipe 31 at the same time. Heat-insulating member 15includes a plating layer 12 constituting an inner air blocking layer,heat-insulating layer 13 and a film layer 14 constituting an outer airblocking layer.

Plastic container 11 has a cubic structure by combining first and seconddivision casings. Plastic container 11 is connected to inflow pipe 30and outflow pipe 31 communicating with the interior thereof. Inflow pipe30 and outflow pipe 31 are formed of a synthetic resin.

Plastic container 11 and pipes 30, 31 are formed of a synthetic resinmaterial, such as PPS, PPA or NY66, mixed with glass fiber. Plasticcontainer 11 and pipes 30, 31 are formed of a member having thethickness of 1 mm to 5 mm.

Plating layer 12 is a thin metal coating (of aluminum, for example)formed by the plating process in such a manner so as to cover the outersurface of plastic container 11. Heat-insulating layer 13 is formed tocover the whole outer surface of plastic container 11 including thebases of inflow pipe 30 and outflow pipe 31. Heat-insulating layer 13 isformed of glass wool, rock wool, urethane foam or polystyrene and thelike. Heat-insulating layer 13 has the heat conductivity of not morethan 0.01 (kcal/hm ° C.). Film layer 14 is formed of a laminate film andsurrounds the whole of heat-insulating layer 13. Film layer 14 andplating layer 12 are formed to prevent the transmission of air.

Plating layer 12 covers the entire outer surface of tank body 11 and thebases of inflow pipe 30 and outflow pipe 31. As a result, the edges ofthe plating layer 12 is exposed only as two annular edges around theouter periphery of inflow pipe 30 and the outer periphery of outflowpipe 31. On the other hand, film layer 14 is formed in the shape of acylinder or a bag by folding a tabular film blank and bonding the edgesthereof to each other. Film layer 14 has two annular edges around theperiphery of inflow pipe 30 and the periphery of outflow pipe 31.Plating layer 12 and film layer 14 are bonded at two points aroundinflow pipe 30 and the periphery of outflow pipe 31. This configurationis effective for suppressing the heat transfer from plating layer 12 tofilm layer 14. Joints 21, 23 between plating layer 12 and film layer 14are referred to as first joints, while joints 20, 22 between film layers14 are referred to as second joints.

FIGS. 4 and 5 show the internal structure of heat storage tank 10. Aplurality of partition plates 40 are arranged in parallel to each otherin the vertical direction in heat storage tank 10. Each space betweenthe plurality of partition plates 40 forms a parallel flow path 41.Parallel flow paths 41 are to supply the engine cooling water invertical direction.

The plurality of partition plates 40 are vertically offset alternatelyin staggered fashion, and are supported by the bottom surface or theceiling of heat storage tank 10.

Turn paths 42, 43 for turning the flow of the engine cooling water areformed on the upper or lower side of the plurality of partition plates40. Turn paths 42, 43 are arranged alternately in the direction in whichpartition plates 40 are arranged. Turn paths 42 turn the upward flowdownward. Turn paths 43 turn the downward flow upward.

The plurality of partition plates 40 are formed of a synthetic resinmaterial integrally with plastic container 11 and pipes 30, 31. Theplurality of partition plates 40 are formed of the thickness of 1 mm to2 mm.

In this configuration, the engine cooling water flows in the pluralityof parallel paths 41 and the plurality of turn paths 42 and 43. Theengine cooling water thus flows in zigzag as indicated by arrows in FIG.5. As a result, the engine cooling water flowing in from inflow pipe 30can flow out from outflow pipe 31 without mixing with the engine coolingwater previously existing inside heat storage tank 10.

A method of manufacturing heat storage tank 10 according to thisembodiment will be explained.

FIG. 6 is a diagram showing the assembly steps, and FIGS. 7 and 8 arediagrams showing the steps of forming film layer 14.

First, plastic container 11 is formed, as shown in (a) of FIG. 6, bycombining first and second division casings 11 a, 11 b.

Next, a thin metal coating is formed, as shown in (b) of FIG. 6, byplating the whole outer surface of plastic container 11. In the process,the thin metal coating is formed in such a manner as to cover therespective roots of pipes 30, 31. Thus, plating layer 12 is formed.

Then, heat-insulating layer 13 is formed on the outside of plating layer12. Specifically, glass wool (i.e. heat-insulating material) is arrangedin such a manner as to cover the whole outer surface of plasticcontainer 11 including the roots of pipes 30, 31 as shown in (c) of FIG.6.

Next, film layer 14 is formed, as shown in (d) of FIG. 6, on the outsideof heat-insulating layer 13.

Specifically, as shown in FIG. 7, a rectangular laminate film 14 a isprepared, and folded back in channel shape as shown in FIG. 8.

Then, as shown in FIG. 9, two end portions 14 b, 14 c of laminate film14 a are heat sealed to each other. As a result, laminate film 14 a isformed in the shape of a rectangular tube.

Then, as shown in FIG. 10, circular holes 140, 141 are formed in theupper parts of the two opposed side walls of laminate film 14 a in theshape of a rectangular tube.

Then, circular holes 140, 141 are extruded by the heat press process,thereby forming cylindrical portions 140 a, 141 a as shown in FIG. 11.

Next, upper end portions 142, 143 of laminate film 14 a in the shape ofa rectangular tube are folded into overlapped form and heat sealed toother. As a result, a heat seal portion 22 (FIG. 3) is formed at theupper end of laminate film 14 a. Heat seal portion 22 represents a partwhere upper end portions 142, 143 are closely attached to each other byheat sealing.

Laminate film 14 a is formed into the shape of a rectangular tube, andupper end portions 142, 143 thereof are hermetically closed. After that,plastic container 11 with plating layer 12 and heat-insulating layer 13is inserted into laminate film 14 a in the shape of a rectangular tubeas described above.

Then, pipes 30, 31 are inserted into cylindrical portions 140 a, 141 a,respectively. As a result, a first gap is created between cylindricalportion 140 a and pipe 30, and a second gap between cylindrical portion141 a and pipe 31.

Lower end portions 144, 145 of laminate film 14 a in the shape of arectangular tube are folded into overlapped form and heat sealed toother ((d) in FIG. 6). As a result, heat seal portion 20 (FIG. 3) isformed at the lower part of laminate film 14 a. Heat seal portion 20represents a part where lower end portions 144, 145 are heat sealed toother.

Then, vacuum is introduced from the first and second gaps describedabove. In addition, cylindrical portion 140 a of laminate film 14 a ofpipe 30 is heat sealed to plating layer 12. In pipe 31, cylindricalportion 141 a of laminate film 14 a is heat sealed to plating layer 12.

As a result, heat seal portions 21, 23 (FIG. 3) are formed on laminatefilm 14 a. Heat seal portion 21 represents a part where cylindricalportion 140 a (FIG. 12) of laminate film 14 a is heat sealed to platinglayer 12 on the outer surface of pipe 30. Heat seal portion 23represents a part where cylindrical portion 141 a (FIG. 12) of laminatefilm 14 a is heat sealed to plating layer 12 on the outer surface ofpipe 31. Thus, the space between plating layer 12 and laminate layer 14a is substantially formed in a vacuum.

According to the embodiments described above, heat storage tank 10includes plastic container 11 for storing the engine cooling water,inflow pipe (first pipe) 30 and outflow pipe (second pipe) 31communicating with the interior of plastic container 11 and formed insuch a manner as to be projected from plastic container 11, andheat-insulating layer 13 arranged to cover the whole periphery ofplastic container 11 and to insulate the engine cooling water in plasticcontainer 11, wherein heat-insulating layer 13 is arranged to cover alsothe roots of pipes 30, 31.

Thus, the heat of the engine cooling water is prevented from beingradiated from the bases of pipes 30, 31. Only one plastic container(tank body) 11 is used, but not two tanks including inner and outercylindrical tanks, thereby reducing the cost. Therefore, the cost can bereduced while at the same time maintaining the insulation effect.

Other Embodiments

The embodiments described above represent a case in which a thin metalcoating is formed as plating layer 12 on the outer surface of plasticcontainer 11. As an alternative for plating layer 12, a thin film madeof a synthetic resin material which can shut off the air may be used.The film material may be formed to cover the exterior of plasticcontainer 11 in place of plating layer 12. In this case, the inner filmlayer replacing plating layer 12 covers the whole tank body 11, and isformed in such a manner as to locate an edge adapted to be bonded withthe outer film layer only around pipes 30, 31.

The embodiments described above represent a case in which the spacebetween plating layer 12 and film layer 14 is formed in a vacuum toimprove the heat insulation characteristic. Nevertheless, the space maynot be formed in a vacuum.

The embodiments described above represent a case in which plasticcontainer 11 is used as a tank body. As an alternative, a metal tank maybe used as a tank body.

The embodiments described above represent a case in which inflow pipe 30and outflow pipe 31 are formed in such a manner as to be projectedoutward at the lower part of the side wall of plastic container 11.However, the invention is not limited to this configuration, but inflowpipe 30 and outflow pipe 31 may be arranged at any point on plasticcontainer 11. Also, in place of the configuration in which two pipes 30,31 are extended independently of each other in spaced relation with eachother, a configuration may be employed in which pipes 30, 31 areadjacent to each other or provided as a single double pipe.

The embodiments described above represent a case in which the enginecooling water is used as the fluid. As an alternative, other fluids suchas the oil may be used.

The embodiments described above represent a case in which heat storagetank 10 is mounted on the vehicle. As an alternative, heat storage tank10 may be used with any of various devices such as a container forinsulating the hot bath water.

While the invention has been described with reference to specificembodiments chosen for purposes of illustration, it should be apparentthat numerous modifications could be made thereto by those skilled inthe art without departing from the basic concept and scope of theinvention.

1. A heat storage tank comprising: a tank body for storing a fluid;pipes communicating with the interior of the tank body and formed toproject from the tank body; and a heat-insulating layer arranged tocover the whole periphery of the tank body including the roots of thepipes and thus to insulate the heat of the fluid in the tank body. 2.The heat storage tank according to claim 1, wherein the tank body isformed of a synthetic resin material, wherein an inner air blockinglayer is formed on the outer surface of the tank body for preventing theair passage, wherein the heat-insulating layer is arranged on theoutside of the inner air blocking layer, wherein an outer air blockinglayer is arranged so as to cover the heat-insulating layer forpreventing the air passage, and wherein the inner and outer air blockinglayers are coupled to each other by the edges thereof, and the spacebetween the inner and outer air blocking layers is hermetically closed.3. The heat storage tank according to claim 2, wherein joints forcoupling the inner air blocking layer and the outer air blocking layerto each other are arranged on the outer periphery of the pipes.
 4. Theheat storage tank according to claim 3, wherein the joints between theinner air blocking layer and the outer air blocking layer are arrangedonly on the outer periphery of the pipes.
 5. The heat storage tankaccording to claim 1, wherein the pipes include a first pipecommunicating with the interior of the tank body and formed in such amanner as to be projected from the tank body for supplying a fluid intothe tank body, and a second pipe communicating with the interior of thetank body and formed in such a manner as to be projected from the tankbody for discharging the fluid out of the tank body, and wherein thetank body comprises a plurality of partition plates arranged therein sothat the influent fluid from the first pipe flows out from the secondpipe after flowing in zigzag in the tank body.
 6. The heat storage tankaccording to claim 5, wherein the pipes are arranged at the lower partof the tank body.
 7. The heat storage tank according to claim 1, whereinthe heat-insulating layer has the heat conductivity of not more than0.01 (kcal/hm ° C.).
 8. The heat storage tank according to claim 1,wherein the fluid is the engine cooling water of the automotive vehicle.